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Scanning tunneling spectroscopy

About: Scanning tunneling spectroscopy is a research topic. Over the lifetime, 7886 publications have been published within this topic receiving 213828 citations.


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TL;DR: It is found that the spin canting in the Fe nanowires monotonously increases towards the step edges.
Abstract: We have performed spin-polarized scanning tunneling spectroscopy of dipolar antiferromagnetically coupled Fe nanowires with a height of two atomic layers and an average separation of 8 nm grown on stepped W(110). Domain walls within the nanowires exhibit a significantly reduced width when pinned at structural constrictions. The lateral spin reorientation in the direction perpendicular to the wires has been studied with subnanometer spatial resolution. It is found that the spin canting in the Fe nanowires monotonously increases towards the step edges.

156 citations

Journal ArticleDOI
TL;DR: It is illustrated that the magnitude of the tunneling enhancement depends on the initial redox state of HS6V6 (V(2+) or V(+*)), and a clear discrimination between the redox-mediated enhanced and the off-resonance tunneling currents I(enh) respective I(T).
Abstract: We report on the construction of an asymmetric tunneling junction between a Au STM tip and a Au(111)-(1 x 1) substrate electrode modified with the redox-active molecule N-hexyl-N'-(6-thiohexyl)-4,4'-bipyridinium bromide (HS6V6) in an electrochemical environment. The experiments focused on the reversible one-electron transfer reaction between the viologen dication V(2+) and the radical cation V(+*). Employing the concept of "electrolyte gating" we demonstrate transistor- and diodelike behavior based on in situ scanning tunneling spectroscopy at constant or variable bias voltages. We derived criteria and verified that the experimental data could be represented quantitatively by a model assuming a two-step electron transfer with partial vibrational relaxation. The analysis illustrates that the magnitude of the tunneling enhancement depends on the initial redox state of HS6V6 (V(2+) or V(+*)). Characteristic parameters, such as reorganization energy, potential drop, and overpotential across the tunneling gap were estimated and discussed. We present a clear discrimination between the redox-mediated enhanced and the off-resonance tunneling currents I(enh) respective I(T) and distinguish between electron transfer in symmetric and asymmetric Au | redox-molecule | Au configurations.

156 citations

Journal ArticleDOI
TL;DR: It is proposed that the outermost layer of the Ge(2)Pt nanocrystal is a germanene layer, in line with a model recently proposed for metal di-(silicides/)germanides: a hexagonal crystal with metal layers separated by semiconductor layers with a honeycomb lattice.
Abstract: We have investigated the growth of Pt on Ge(1 1 0) using scanning tunneling microscopy and spectroscopy. The deposition of several monolayers of Pt on Ge(1 1 0) followed by annealing at 1100 K results in the formation of 3D metallic Pt-Ge nanocrystals. The outermost layer of these crystals exhibits a honeycomb structure. The honeycomb structure is composed of two hexagonal sub-lattices that are displaced vertically by 0.2 A with respect to each other. The nearest-neighbor distance of the atoms in the honeycomb lattice is 2.5 ± 0.1 A, i.e. very close to the predicted nearest-neighbor distance in germanene (2.4 A). Scanning tunneling spectroscopy reveals that the atomic layer underneath the honeycomb layer is more metallic than the honeycomb layer itself. These observations are in line with a model recently proposed for metal di-(silicides/)germanides: a hexagonal crystal with metal layers separated by semiconductor layers with a honeycomb lattice. Based on our observations we propose that the outermost layer of the Ge2Pt nanocrystal is a germanene layer

155 citations

Journal ArticleDOI
TL;DR: In this paper, the basic physical content of the mechanisms responsible for phonon broadening in core-level spectroscopy, intramolecular vibrational excitation in resonant electron scattering, phonon excitation and hot-electron-induced resonant desorption is shown to be similar.
Abstract: Excitation of a localized oscillator or phonon due to transient charge transfer into and out of electronic states linearly coupled to the oscillator is considered within several different contexts. Specifically, the basic physical content of the mechanisms responsible for phonon broadening in core-level spectroscopy, intramolecular vibrational excitation in resonant electron scattering, phonon excitation in resonant electron tunneling through quantum-well heterostructures, and hot-electron-induced resonant desorption is shown to be similar. Existing exact solutions to the scattering and tunneling problems are here adapted to resonant desorption and numerical consequences--such as excitation and desorption probabilities and translational energy distributions--are obtained. These results and insights are considered in the light of a semiclassical wave-packet-dynamics model, which previously had been developed to account for observed nonthermal, laser-induced desorption in the system NO/Pt(111).

155 citations

Journal ArticleDOI
TL;DR: The spatial distribution of the vibrational intensities exhibited pi(g)-orbital (perpendicular to surface) symmetry of O2 with the molecular axis along the [001] direction, attributed to resonant inelastic electron tunneling.
Abstract: Inelastic electron tunneling spectroscopy and microscopy with a scanning tunneling microscope revealed two vibrational modes showing a decrease in conductance at +/-82.0 and +/-38.3 mV sample bias for single oxygen molecules chemisorbed on the fourfold hollow sites of Ag(110) surface at 13 K. The spatial distribution of the vibrational intensities exhibited pi(g)-orbital (perpendicular to surface) symmetry of O2 with the molecular axis along the [001] direction. These results are attributed to resonant inelastic electron tunneling.

155 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202345
202289
2021128
2020143
2019134
2018159